Shutdown seal control for elastic fluid compressors



Patented July 8, 1952 UNITEDV I STATES William H.v Church, Jersey City,N. J., assignor to Worthington Pump and Machinery Corpos ration,Harrison, N. J., a corporation of Delaware Application April 25, 1950,Serial No. 158,015

l0 Claims. l

This invention relates generally to elastic uid compressors and moreparticularly to an air valve control for operating the shut down sealtherein where complete failure of the main service pump and theauxiliary oil pump occurs.

While it is not intended to so limit the present invention, it isparticularly applicable to centrifugal compressors utilized inrefrigerating apparatus for compressing the vapors of volatile liquidrefrigerant such, for example, as trichlorofluoromethane, methylenechloride, etc.

In centrifugal compressors to prevent gas loss usually the compres-sorsare designed whereby gas leakage occurs only along the rotor.Accordingly, means are further provided to prevent gas leakage along theshaft by providing an inner seal when the compressor is operating and anouter seal for shut downfperiods or when emergency shut down occurs, theinner seal and outer Yseal generally being operated in conjunction witha lubricating system which includes a lubricant pump operated off therotor. In addition, for starting up and shutting down, and in `the eventof pressure reducing below a predetermined minimum in the lubricationsystem, an auxiliary pump is generally provided to maintain thelubricant pressure in the lubrication system and to maintain thepressure a given period of time to prevent the outer seal from closingbefore the compressor is at rest.

It has been found that if auxiliary pump failure occurs, when the mainpump is not in operation or total power failure occurs, the lubricantpressure will immediately drop causing the, shut down seal to closebefore the compressor has come to rest resulting in the seal beingdamaged and, as a consequence thereof, providing an escape outlet forvthe fluid in the compressor and further necessitating immediatereplacement of the shutdown seal to eliminate this dangerous hazard.

The present invention contemplates a novel construction which providesmeans for controlling the closing of the shut down seal where the mainand the auxiliary pumps fail with the power on and in addition wheretotal power failure occurs, provides air pressure means for coactingwith said means, to maintain said shut down seal open until thecompressor is at rest and only allows the shut down seal to close in asafe manner without damage to the seal.

Accordingly, it is an object of the present invention to provide meansfor controlling the closing of the shut down sealV whereby it will betimed to close after the compressor comes'to rest.

It is another object of the present invention to provide means formaintaining. the shut down seal openvunder varying emergency conditionssuch as where both the main pump and the auxiliary pump fail while thepower remains on, or when total power failure or other similar conditionarises in the operation of the compressor.

With these and other objects vin View, as may appear from theaccompanying specification, the invention consists of various featuresof construction and combination of parts, .which will be first describedin connection withV the accompanying drawing, showing a shut down sealcontrol for elastic fluid compressors of a preferred form embodying theinventionfand the features forming the invention will be specificallylpointed out in the claims.

In the drawings:

Figure l is a diagrammatic sketch of atypical compressor systemincluding the invention. l

Figure'2 is a cross-section of one type of air operated valve, used inthe present invention.-l

Referring more particularly to the drawings, Figure l illustrates atypical compressor system showing generically a compressor casing Ihaving a rotor shaft 2 extending through said casing connected by acoupling 3 to step up gears 4 whichV are in turn connected to a primemover (not shown), being any suitable typefor operating the compressorI. The step up gears may also be any suitable type easily purchasableonthe open market and are therefor generically indicated. The rotor shaft2 provided for the -compressor has a line bearing 5 at one end andthrust bearing 5 at the other end to allow for relatively frictionlessrotation of the-rotor shaft 2 during operation. y

The shut down seal system is indicated in the drawing at the linebearing end of therotor shaft 2. It is understood that while this typeof shut down seal system is shown lthat any other suitable type Voffluid operated shut down seal system would suffice to describe thisinvention.,

Accordingly, Figure lshows a Isealing collar 1, which is an annularstructureiixedly mounted on the rotor shaft 2. A sealing sleeve 8, asubstantially hollow cylindrical structure', is slidably mounted aboutthe rotor shaft 2 for movement towards and away from the sealingcollar'l.` At its inner aspect it is provided with a sealing face 9having alsealing insert l0, -of suitable resilient material which willlengage theV sealingr collar 1 in fluid tight relationship when thesealing sleeve 8 is moved towards the sealing collar l. When thesealingv insert I0 is thusin contact with'the Sylphon bellows l2, whichis a tube-like resilientl structure is `further provided between theback plate I3 'of the end chamber II and the sealingl face 9 to preventgases escaping from the end chamber II through the opening provided to;allow the rotor shaft 2 with the sealing sleeve S mounted thereabout topass therethrough.

The sealing sleeve 8 extends along the rotor shaft 2 through the backplate I3 to 'contact in pivotal engagement an annular portion I4 of alever I5.

Lever I5 lies perpendicular to the axis of the rotor shaft 2 and pivotson a fulcrum I6 at one end. And the other end is pivotally connected toa piston rod I'I. nected to a seal operating ,piston I8 and is xedlyattached for slidable movement therewith, the seal operatingpiston VI8being reciprocatable in a seal operating cylinder I2 mounted on thecompressor, as is clearly shown Yin Figure 1 of the drawings.

Seal operating cylinder 'It is substantially cy lindrical in shape andlies so that its axis is in a parallel plane with that of the ro-torshaft 2. The rear portion of the cylinder I9 is provided with an openingand bearing structure 2| for thepassage of thepiston rod I1 therethroughtothe seal operating piston I8. Mounted concentrically about the pistonrod I1 and between the seal operating piston I8 and the real portion 2i)of the cylinder I9 is a resilient spring member 22 which normallymaintains the piston in a for- Ward position in the cylinder. The seal`operating cylinder I9 is provided forwardly-of this normal position ofthe piston member I8 with ya seal operating cylinder inlet port -23whereby high pressure lubricant from the lubrication system to behereinafter described may be forced into the seal operating cylinder I9to force the piston member rearwardly against the resilient springmember 22.

A safety .or Vlimit switch 24, also indicated in Figure 1, is operatedfrom the outer end oi the piston rod I1. When the piston I 8 is forwardin thercylinder I9, the limit switch will be open and the yprime mover(not shown) operating therethrough cannot be started. However, when thepiston member I8 is moved rearwardly by the action of the high pressurelubricant as hereinafter described the piston rod I'I will in turn bemoved whereby lthe Vouter end 25 willrmake contact with the limit switch24 to allo-W the prime mover (not shown) to be placed in operation.

Movement of the piston rod I1 will in turn cause the 'lever arm I5, `andthe sealing sleeve v8 connected thereto to be moved back and forthwhereby the sealing insert I0 will engage and disengage the sealingcollar I all of the above being clearly shown in Figure 1 of thedrawings.

The operation and control of the seal operating cylinder I9 which inturn controls the operation of the shut down seal system as abovedescribed is best described in connection with both the lubricationsystem, :also indicated in Figure l of the drawings and the controlscooperatively connected into the lubrication system to accomplish the,desired purpose. It is understood that while this type of lubricationsystem is sho-wn 'that any type system which will supplyfluid at highpressure for the operation of the Vseal operating cyl- Piston rod I1 isfixedly con-V inder may be utilized with the air valve control system,shown herein and hereafter described.

Accordingly, beginning at 'the thrust bearing end of the compressor, the`end of the rotor shaft 2 extends into a fully enclosed reservoir or oilsump 3l, having a service 4pump 32 and an auxil iary pump 33 therein forsupplying oil or other lubricant at high pressure to the lubricationsystem.

.Auxiliary lpump v3-3 is drawn iby an electric motor 34 and is utilizedto provide lubricant at high pressure to the lubrication system whenstarting up and shutting down and in case of failure of the service pump32, to supply lubricant at a pressure above a predetermined minimumsetting. An automatic pressure switch` (not shown) starts the auxiliarypump when the oil .pressure from the service pump falls below thepredetermined minimum setting.

Figure 1 further shows the rotor shaft 2 having -a bevel gear iisatA theend thereof which drives a second bevel gear 36 iixedly connected to ashaft 3l which is in turn connected to the service pump 32. rlherefore,as the r-otor shaft 2 turns it drives the bevel gears'35 and 3S drivingthe shaft 31 which `in turn drives the service pump 32. Oil or .othersuitable lubricant is thus drawn from the reservoir or `oil sump 3| intoopening 38 in the service pump 32 and discharged from the service pump32 .at high pressure into a conduit 39. Thereafter .the oil is forcedVthrough the first stage of a four-way by-pass valve Minto an cilstrainer 4I whence it is returned to the second stage of the by-passvalve 40. Apcrtion of the lubricantpassing from the second stage of theby-pass Valve 40will .pass to an oil pressure control 42 .provided :toby-pass a quantity of oil back to the reservoir during operation ofeither the service pump 32 or the auxiliary pump 33 to maintain vaconstant predetermined pressure maximum at the discharge sides oi thepumps. The remaining portion of the lubricant passing out of the secondstage Iof the by-pass valve 40 will pass through an oil cooler'43 andthen to the main high pressure supply line 44 whence various-conduits asshown at 45, 4B and l 41, connected thereto pass the lubricant to thevarious portion-s of the Ycompressor which utilize the high .pressurelubricant such as the thrust bearing 6, line bearing 'I and shut downseal system, etc.

The high pressure lubricant is returned from these various portions notforming part of the present invention by gravity ilow to the lowpressure line 48 which conducts it to the reservoir or oil sump 3|.

Auxiliarypurnp 33 utilized for starting up and shutting down in .case offailure of the service pump 32, also shownvin Figure 1, is connected tothe electric motor .34 by a shaft 49. The electric motor which may beoperated manually or made automatically responsive to the pressuresupplied by the service pump 32. When the .electric motor 34 is inoperation it causes the pump to draw lubricant from the reservoirthrough an opening 5i! therein which is forced out at high pressurethrough .line 5I. .Line 5I will allow a portion of the fluid to passthrough the oi] pressure control 42 above described to allow a certainportion of the fluid to by-pass back to the reservoir. The remainingportion of theruid will pass through check valve 52 directly to the oilcooler member 43 where the flow of uid is identical with the .oW throughthe oil cooler as above described',

' 5 The shut down seal control, receives the high pressure lubricantthrough an aircontrol system which operates in response to the change inpressure in the lubrication system( Thus high pressure line 41 whichreceives high pressure fluid from the main high pressure line 44 leadsto a conduit `41a in turn connected to an air valve 68 hereinafterdescribed.

In the conduit 41a a solenoid oil valve 6| is positioned to be opened orclosed to allow high pressure fluid to flow through conduit 41a.Solenoid oil valve -6| is normally open (no current flowingtherethrough) and is operated in response to a pressure switch |52yconnected to line 411) which receives high pressure iiuid also from highpressure line 41. Pressure switch 62 is connected in the same electricalcircuit with the solenoid oil valve 6| and is set so that when'the fluidpressure in line 41D reaches a predetermined mini-V mum setting thecurrent to the solenoid oil valve 6| will be broken, deenergizing thesolenoid oil valve El whereby it will be open pass therethrough to theair valve V80. It is believed that it is obvious that when the pressuredrops below the predetermined minimum that the circuit to the solenoidVvalve will be closed causing it to energize and close the valve in theconduit 41a whereby iiow therethrough is prevented. Solenoid oil valve8| and pressure switch 62 may be of any suitable type of which there aremany easily purchasable on the open market.

Air 'valve 'member Air valve 60 is threadably connected to conduit 41aby inlet port 63 as is clearly shown in Figure 2 of the drawing, andincludes, a connecting base 64, a middle body portion 65 and a coverportion 88.

be conducted to the reservoir, or as shown inl the float trap 68, f

Figure l of the drawings to whence it then passes to the common returnline 48 to be passed back to the reservoir'I.'

Connecting base 64 is further provided with a cylindrical bore 69, intowhich is fitted in fluid tight relationship a cylindrical projection 10on the lower portion of the middle body portion '65. The middle bodyportion '65 is a substantially cylindrical member, having an enlargedcupshaped flange 1| at the outer end thereof which engages a secondcup-shaped flange 12 formed on the annular cover member 66 whereby achamber 13 is formed in this portion of the air valve 60. Adapted to beheld between the flanges 1| and 12 is a diaphragm member 14 made ofrubber or other suitable material which, in the assembled position, willbeheld in the medial plane ofthe chamber 13 by suitable threaded meanssuch as bolts 15. The chamber 18 will thus be ldivided into an air tightupper chamber 13a and fluid tight lower'chamber 13b, all of which isclearly shown in Figure 2 of the drawings.V

Inlet port 63 enters the connecting base 64 in the axial line of thecylindrical bore 68 and communicates with a valve yport 15 formed inavalve seat 11 fitted into the base of the cylindrical'bore 69 betweenthe bore 69 and the inlet port 63 whereby the valve portf16 will providecommunication therebetween. An exhaustport 18 is provided in the sidewall of the cylindrical bore B9 above the valve port 1:6 which isthreadably to allow fluid tov 6 connected to aV conduit 19"leading tothe seal operating inlet port 23 above described, which acts to conductthe lubricant fluid both towards and away from the seal operatingcylinder.

Valve port 16 is engaged valve head 80, formed integrally at the innerend of an elongated valve stem 8| extending through a valve guide bore82,intermediate chamber 83, and enlarged chamberA 84 formed in themiddle body portion 65, to pass through the diaphragm member 14 to whichit is connected in air tight relationship by means of a lowervcouplingportion 8 5 threadably mounted on the Velongated valve stem 8| below thediaphragm 14, and an upper coupling portion 86 which s queezes thediaphragm therebetween when the nut member 81 is threaded into the endof the valve stern 8| into tight abutment with the upper couplingportion8B. All of the above being clearly shown in Figure 2 of the drawings.

Valve port 116 will be normally maintained open by a valve spring 88,which is mounted concentrically about the valve stem 8|, `in theenlarged chamber 84, abutting the inner end thereof on one side, and onthe outer end, a projection 89 formed on the lower coupling 85. Theprojection 89 is slidably mounted in the-outerv end of enlarged chamber84, and will compress the valve spring88, when as hereinafter describedair pressure acting in the upper chamber 13ay against the diaphragmmember 14 will move the valve stem 8| and theV upper coupling 85inwardly, causing the valve head to close the valve port 10. f

When valve port 16 is thus closed, any back pressure in line 18 willtend to force lubricant operating fluid along the -valve stem 8| to theintermediate chamber 83.

Intermediate chamber 83 is connected by transverse passages v8|)radially spaced in the projection 10 to an annular chamber 9|, formed inthe upper part of thel cylindrical bore 69, which in turn communicates`with the return passage 61. Thus any lubricant fluid forced along thevalve stem 8| to `the intermediate chamber 83 will pass Yby differentialpressure from'the intermediate chamber l83 through the transversepassage 80-into the annular chamber 9| and thence through the returnpassage 61 to the reservoir or sump 3|, as above described.

M cans for delivering air pressure to the air valve Upper chamber 13aformed in the air valve 60 communicates by an air inlet port |00 in thecover member 66, with an air conduit |0| threadably connected thereto asshown in Figure 2.

Air conduit |0| is in turn connected to an air receiver or reservoir |02through a solenoid air valve |03. Air receiver |02 may be any suitabletype of compressed air storage tank, which are well known in the art andeasily purchasable on the open market.

Solenoid valve |03 mayalso be any suitable type which will be normallyopen when there is noV current passing therethrough. However, wheneverthe power is on and vcurrent is flowing therethrough it will be closed,lthus preventing air under pressure in the air receiver |02 from owingthrough theair conduit` |0| to the air inletport |00 and the upperchamber 13a, as is clearly shown in Figures land 2 of the drawings. r

Ihe air pressurefin air receiver |02 will be maintained at some suitablepredetermined fpressure suicient to close the air valve 60 whenever andclosed by a needlek 7 the solenoid valve |03 is opened, by a suitablecompressing means (not shown) which may be operated either off someportion of the compressor or rotor shaft 2 or separately by a separateprime mover suitable therefor.

The compressing means (not shown) is connected by a suitable connectingconduit IM in which is provided an air check valve It and an air orice|66. Air orifice |05 may be any suitable type of constricting meansacross some portion of the connecting conduit |04 between the checkvalve |05 and the air receiver |2, such as a steel plate with a sizedopening |01 which will limit the amount of air delivered to the'airreceiver |92 after the solenoid air valve |03 is opened, such that theamount of air delivered to the air receiver will be less thanthe amountof air bled out through the bleeder openings |88 and |09, shown on theair valve 60 in the cover member 66 thereof, and provide communicationwith atmospheric pressure through 'the air inlet part to the upperchamber 13a. It being understood that while these bleeder openings areshown in the cover member yt6, in the preferred form, it is obvious thatthey may be placed anywhere along the conduit |0| between the solenoidair valve |93 and the air valve 553 to effect this result.

To regulate the amount of air bled out of upper chamber 13a, bleederopening |09 is provided with a needle-like bleeder screw Ilii forengagement therewith, to regulate the size of the opening, and a bleederscrew locking nut I I I to hold it in this position. This will beimportant as hereinafter described to allow the .air valve 6|) to betimed to open so as to correlate with the speed of the rotor shaft 2, sothat the shut down seal will not close until the compressor has come torest.

Operation In operation, when the power is turned on eurrent passes to alocking switch ||2 causing it to raise, and to .both solenoid valves Siand IUS causing them to energize and accordingly close.

Auxiliary pump motor '.54v may then be started, driving shaft 49 and theauxiliary oil pump. Thus lubricant uid will be drawn from the reservoir3| into opening `5|) and discharged into line 5| under pressure. Itpasses through line 5I, check valve 52 and oil cooler 63 to the highpressure line 44, whence it is passed to the respective conduits 45, 4Sand 51 as above described.

High pressure lubricant in line 41 passes to conduits 41a and 41h.However, until the pressure acting therein reaches a predeterminedminimum, the pressure switch 62 will not be acti- .vated to open thesolenoid oil valve 6| by opening the circuit thereto. However, when thepredeter-mined minimum pressure is reached the pressure switch 62 opensthe circuit to the sole-v noid oil valve 6| which allows lubricant fluidunder Vhigh pressure to iiow to the. airfvalve EQ. Since the solenoidair valve |63 is closed, only atmospheric pressure will be actingagainst the diaphragm member 14 through the bleeder opening |08 andaccordingly Ithe air valve Awillbe held open by the spring member Si),allowing lubricant fluid to pass through the inlet port El?, valve port16, into the cylindrical bore 68, and out through the outlet port 18, tothe conduit 19; Thereafter it passes to the seal operating cylinderinlet port 23 and into the cylinder 'I9 to act against the piston memberI3, forcing the piston member I 8, outwardly, vandas above described 8causing the shut down sealing sleeve .8 to move out of contact with thecollar 1. rEhe limit switch is also closed so that prime mover (notshown) driving the compressor may be started.

After the compressor is started, the rotor shaft 2 will drive the mainservice pump 32, and when a predetermined minimum pressure is reachedthe circuit to the auxiliary pump motor 34 will be automatically openedallowing the auxiliary pump 35 to stop. However, it is understood thatif the pressure drops below the predetermined minimum the circuit to theauxiliary pump motor 34 will be closed and cause the auxiliary oil pump33 to again start operating.

As long as the lubricant fluid pressure remains above the predeterminedminimum pressure necessary to maintainl the circuit to the solenoid oilvalve V6| open, lubricant iluid under pressure will be acting againstthe piston I8 in the shut down seal cylinder |9 and maintain the shutdown seal iii, open and out of contact with the collar Where, however,failure of both the main service pump and the auxiliary oil pump occurs,with the power on, the pressure switch b2 responsive to the pressure inline 5122, will close the circuit to the solenoid oil valve 5|,energizing it and causingthe valve to close which prevents lubricantiluid in line 19 from returning through the air valve El] through line41a to line l? as the pressure reduces in these lines.

Accordingly, with the solenoid oil valve 5| closed the lubricant fluidwill have a certain amount of back pressure which will prevent thepiston member I8 from moving forwardly in the seal operating'cylinderIS, thus maintaining the shut down seal I i) open. In addition, theclearance between the valve stem 8| and the valve guide bore 82, will besuch that the lubricant liuid may bleed slowly along the valve stem 8|to the intermediate chamber 83 and thence to the return passage G1 asabove described so that the shut down seal sleeve 8 will move slowlyinwardly as the pressure reduces, the timing thereof being regulated inaccordance with the time required to bring the compressor to rest as thereduction in lubricant pressure will cause the prime mover (not shown)to stop driving the compressor as soon as the limit switch 24 opens.

Where failure of, both the main service pump 32 and the auxiliary pump33, and the power fails, both solenoid valves 5I and |83 will open.

As soon as solenoid valve |93 opens, air pressure will pass from conduitlili to an inlet port I into chamber 13 where it will act against theupper surface of the diaphragm member 1li forcing it downwardly which intime forces the valve stem 8| and the valve head 8|) downwardly closingthe valve port 16, and compressing the spring member 88 as abovedescribed. rhis prevents the lubricant uid from passing through the airvalve 6D to the conduit 41a and thence to 0:1 as the pressure reduces inthe system, and accordingly the seal operating cylinder will under'theseconditions have sufcient pressure acting against the piston member I 8to maintain the shut down seal I0 open.

The air in receiver m2 begins to bleed oil through bleeder means |98 and|99 faster than it can enter H32 thereby reducing air pressure inchamber '13. After a time greater than required for the compressor tostop rotating this air pressure will be sufliciently low to allow spring8B to open valve port 16 so lubricant can return to system through linei1 and allow shut down seal insert I0 to make contact with seal collar1.

9 The compressor is at rest before the aforesaid contact is made.

While one form of this invention has been illustrated and described, it'is understood that the invention is not to be limited to the specificconstruction orA arrangement of parts shown, but that they may be widelymodified within the invention dened by the claims.

What is claimed is:

1. In a control for a shut down seal system on elasticv uid compressorsoperated by a lubrication system thereon having a main service pump andan auxiliary pump including, aV casing, a rotor shaft extending throughsaid casing, a seal collar xedly connected to said rotor shaft, a shutdown seal movably mounted on said rotor shaft for air tight engagementwith said seal collar, a lever pivotally connected to said shut downseal for moving it into and out of engagement with said seal collar,cylinder and piston elements in said compressor for operating said leverresponsive to the lubricant pressure in said lubrication system, aconduit for conducting lubricant uid to and from said lubrication systemto said cylinder element, and an air valve connected in said conduitmaintained normally open, the combination with said air valve of, meansin said conduit to prevent fluid from returning to the lubricationsystem when the pressure in said lubrication system drops below apredetermined minimum, and means in the air valve coacting with saidmeans in the conduit for allowing said lubricant uid to return slowlythrough the air valve when the pressure drops below the predeterminedminimum to' allow the compressor to be brought to rest before the shutdown seal closes. y

2. In a control for a shut down sealsystem on elastic fluid compressorsoperated by a lubrication system thereon having a main service pump andan auxiliary pump including, a casing, Va rotor shaft extending throughsaid casing, a seal collar fixedly connected to said rotor shaft, a shutdown seal movably mounted on said rotor shaft for air tight engagementwith said seal collar, a lever pivotally connected to said shut downseal for moving it into and out of engagement with said seal collar,cylinder and piston elements on said compressor for operating said leverresponsive to the lubricant pressure in said lubrication system, aconduit for conducting lubricant fluid toA and from said lubricationsystem to said cylinder element, and an air valve connected in saidconduit maintained normally open, the combination with said air valveof, means for delivering suicient air pressure to immediately close saidair valve to prevent the return of fluid through said conduit whencomplete power failure occurs, and means for equalizing said airpressure to allow said air valve to open in accordance.

with the predetermined time required forv the compressor to come to restbefore the shut down seal closes. y y

' 3. In a control for a shut down seal system on elastic uid compressorsoperated by a lubrication system thereon having a main service pump andan auxiliary pump including, a casing,

a rotor shaft extending through said casing, a

seal collar iXedly connected to said rotor shaft, a shut down sealmovably mounted on said rotor shaft for air tight engagement with saidseal collar, a lever pivotally connected to said shut down seal formoving it into and out of engagementwith, said seal collar, cylinder andpiston elements on said compressor for operating said lever responsiveto the lubricant pressure in said lubrication system, a conduit forconducting lubricant fluid to and from said lubrication system to saidcylinder element, and an vair valve connected in said conduit maintainednormally open, the combination with said air valve of, means in saidconduit to prevent fluid from returning to the lubrication system whenthe pressure in said lubrication system drops below a predeterminedminimum with the power on, means for delivering sufficient air pressureto immediately close said air valve to prevent the return of duidthrough said conduit when the pressure in said lubrication system dropsbelow a predetermined minimum and there is a complete power failure,means coacting with said means for delivering air pressure forequalizing said air pressure to allow said air valve to open, and meanscoacting with each of the above mentioned means for allowing thelubricant fluid to return to said lubrication system to allow thecompressor to come to rest before said shut down seal closes.

4. In a control for a shut down seal system on elastic fiuid compressorsoperated by a lubrication system thereon having a main service pump andan auxiliary pump including, a casing, a rotor shaft extending throughsaid casing, a seal collar fxedly connected to said rotor shaft, a shutdown seal movably mounted on said rotor shaft for air tight engagementwith said seal collar, a lever pivotally connected to said shut downseal for moving it into and out of engagement` with said seal collar,cylinder and piston elements on said compressor for operating said leverresponsive to lubricant iiuid under pressure from said lubricationsystem, a conduit for conducting lubricant fluid under pressure to andfrom said cylinder element and an air valve comprising, inlet meansformed on Ysaid valve and connected in said conduit, a cylindrical borein said valve communicating with said inlet means through a valve port,outlet means from said cylindrical port and connected to said conduit, avalve guide in said bore and having an elongated valve stem slidablymounted therein, said valve stem provided with a Valve head at one endfor engagement with said valve port, resilient means mounted about saidvalve stem for maintaining said valve port normally open, a chamber insaid air valve provided with a diaphragm thereacross and connected tothe other end of said valve stem for moving said valve head intoengagement with said valve port responsive to air pressure delivered tosaid chamber on at least one side of vsaid diaphragm, the combinationwith said air valve of, a solenoid valve in said conduit on theupstreamside of said valve for closing said conduit to prevent lubricant fluidfrom returning when the pressure in the lubrication systeml drops belowa predetermined minimum when the power is on, and return means formed insaid air valve to coact with said solenoid valve to allow the lubricantto be returned slowly to the lubrication system so that the shut downseal will close in accordance with the stopping time of said com-'-pressor.

5'. In a control for a shut down seal system on elastic fluidcompressors operated by a lubrication system thereon having a mainservice pump and an auxiliary pump including, Va casing, a

rotor shaft extending through said casing, a seal collar xedly connectedto said rotor shaft, a shut down seal movably mounted on said Urotorshaft for air tight engagement with said seal collar, a. lever pivotallyconnected to said shut down seal for moving it into and out ofengagement vwith said seal collar, cylinder and piston elements on saidcompressor for operating said lever responsive to lubricant fluid underpressure from said lubrication system, a conduit for conductinglubricant fluid under pressure to and from said cylinder element and anair valve comprising, inlet means formed on said valve and connected insaid conduit, a cylindrical bore in said valve communicating with saidinlet means through a valve port, outlet means from said cylindricalport and connected to said conduit, a valve guide in said bore andhaving an elongated valve stem slidably mounted therein, said valve stemprovided with a valve head at one end for engagement with said valveport, resilient means mounted about said valve stem for n ivaintainingsaid valve port normally open, a chamer in said air valve provided witha diaphragm thereacross and connected to the other end of said valvestem for moving said valve head into engagement with said valve portresponsive to air pressure delivered to said chamber on at least oneside of said diaphragm, the combination with said air valve of, asolenoid valve in said conduit on the upstream side of said valve forclosing said conduit to prevent lubricant fluid from returning when thepressure in the lubrication system drops below a predetermined minimumwhen the power is on, and return means in said air valve to coact withsaid solenoid valve including, an intermediate chamber formed in saidvalve guide about said valve stem to receive returning fluid underpressure forced therealong from said cylindrical bore, an annular returnpassage formed in said cylindrical bore about said valve guide,transverse passages radially spaced in said valve guide connecting saidintermediate chamber and said annular return chamber, and a returnpassage communicating with said annular return chamber for leadingreturning lubricant fluid back to said lubrication sys-V tem to allowsaid shut down seal to close in accordance with the stopping time cfsaid compressor.

6. In a control for a, shut down seal system on elastic fluidcompressors operated by a lubrication system thereon having a mainservice pump and an auxiliary pump including, a casing, a rotor shaftextending through said casing, a seal collar Xedly connected to saidrotor shaft, a shut down seal movably mounted on said rotor shaft forair tight engagement with said seal collar, av lever pivotally connectedto said shut down seal for moving it into and out of engagement withsaid seal collar, cylinder and piston elements on said compressor foroperating said lever responsive to lubricant fluid under pressure fromsaid lubrication system, a conduit for conducting lubricant fluid underpressure to and from said cylinder element and an air valve comprising,inlet means formed on said valve and connected in said conduit, acylindrical bore in said valve communicating with said inlet meansthrough a valve port, outletV means from said cylindrical port andconnected to said conduit, a valve guide in said bore and having anelongated valve stem slidably mounted therein, said valve stem providedWith a valve head at one end for engagement with said' valve port,resilient means mounted about said valve stem for maintaining said valveport normally open. a chamber in said air valve provided with adiaphragm thereacrcss and` connected to the other end ofzsaid valvestemfor moving said valve head into engagement with said valve portresponsive to air pressure delivered to said chamber on at least one;side of said diaphragm, the combination with said. air valve of, aninlet port communicating with said chamber on one side of saiddiaphragm,an air receiver having sufficient air pressure therein for initiallyclosing said air valve, a conduit connecting said air receiver with saidinlet port so that said air pressure may act against the diaphragm,means in said conduit normally closed when the compressor is inoperation, adjustable meansk on said air valve to equalize the pressurein said chamber to atmospheric pressure, means on said air receiver toconstrict the-.amount kof pressure supplied to said receiver whenthe'initial pressure drops therein, said adjustable'- means set to allowmore air to bleed from said chamber than can be passed to said airreceiver whereby when the means in said conduit opens to pass airpressure to said chamber the air valve will be closed initially by saidpressure but will slowly open on equilization of the pressure to allowthe shut down seal to close in accordance withv the stopping time ofsaid compressor.

'7. In the control for the shut down sealsystem as claimed invclaim 6wherein said adjustable means on the air valve comprises, at leastonebleeder opening, a bleeder screw for regulating the size of said bleederopening, and a lock nut for locking said bleeder screw in thepredetermined timing position to allow the air valve to open whereby theshut down seal will close in accordance with the stopping time of thesaid compressor.

8. In the control for the shut down seal system as claimed in claim 6whereinsaid means to constrict the amount of pressure supplied to saidair receiver is a restricted orifice on the upstream side of the airreceiver which coacts with the adjustable means.

9. In a control for a shut down seal system on elastic fluid compressorsoperated by a lubrication system thereon having a main service pump andan auxiliary pump including, a casing, a rotor shaft extending throughsaid casing, a-seal collar xedly connected to said rotor shaft, a shutdown seal movably mounted on said rotor shaft for air tight engagementwith said seal collar, a lever pivotally connected to saidv shut downseal-for moving it into and out of engagement withsaid seal collar,cylinder and pistonv elements on said compressor for operating saidlever responsive-to lubricant fluid under pressurefrom said lubricationsystem,'a conduit for conducting lubricant iiuid under pressure to andfrom` said cylinder element and an air valve comprising, inlet mea-nsformed on said valve and connected in said conduit, a cylindrical boreinsaid valve communieating with said inlet means through a valvezport,l

outlet means from said cylindrical port and connected to said conduit, avalve guide in said bere and having an elongated valve stem slidablymounted therein, said valve stem provided with a valve head at one endfory engagement with said valve port, resilient means mounted about saidvalve stem for maintaining `said valve portnormally open, a chamber insaid air valve provided with a diaphragm thereacross and connected tothe other end of said valve stem for moving saidY valve head intoengagement with said valve port responsive to air pressure delivered tosaid chamber on at least one side of said diaphragm, the combinationwith said air valve of, a solenoid valve in said conduit on the upstreamside of said valve for closing said conduit to preventI lubricant iiuidfrom. returning when the pressure in the lubrication system drops belowa predetermined minimum when the power is on, return means formed insaid air valve to coact with said solenoid valve to allow the lubricantto be returned slowly to the lubrication system, an air inlet portcommunicating with said chamber, means con nected to said air inlet portto deliver air to said chamber on one side of said diaphragm when thereis complete power failure to force said valve head to close said valveport, means in said inlet port for equalizing the pressure in saidchamber to atmospheric pressure to allow said valve port to openresponsive to the resilient member about the valve stem, means on saidair receiver to restrict the pressure supplied thereto to allow saidequalizing means and said return means to pass the lubricant fluidslowly back to the lubrication system whereby the shut down seal willclose in accordance with the stopping time of said compressor.

10. In a control for a shut down seal system on elastic fluidcompressors operated by a lubrication system thereon having a mainservice pump and an auxiliary pump including, a casing, a rotor shaftextending through said casing, a seal collar iixedly connected to saidrotor shaft, a

shut down seal movably mounted on said rotor .f

shaft for air tight engagement with -said seal collar, a lever pivotallyconnected to said shut down seal for moving it into and out ofengagement with said seal collar, cylinder and piston elements cn saidcompressor for operating said lever responsive to lubricant fluid underpressure from said lubrication system, a conduit for conductinglubricant fluid under pressure to and from said cylinder element and anair value comprising, inlet means formed on said valve and connected insaid conduit, a cylindrical bore in said valve communicating with saidinlet means through a valve port, outlet means from said cylindricalport and connected to said conduit, a valve guide in said bore andhaving an elongated valve stem slidably mounted therein, said valve stemprovided with a valve head at one end for engagement with said valveport,

reilient means mounted about said valve stem for maintaining said valveport normally open, a chamber in said air valve provided with adiaphragm thereacross and connected to the 14 other end of said valvestern for moving said valve head into engagement with said valve portresponsive to air pressure delivered to said chamber on at least oneside of said diaphragm, the combination with said air valve of, asolenoid valve in said conduit on the upstream side oi said valve forclosing said conduit to prevent lubricant fluid from returning when thepressure in the lubrication system drops below a predetermined minimumwhen the power is on, return means formed in said air valve to coactwith said solenoid valve including an intermediate chamber formed insaid valve guide about said valve stem to receive returning lubricantfluid forced therealong under pressure from said cylindrical bore, anannular return passage formed in said cylindrical bore about said valveguide, transverse passage radially spaced in said valve guide connectingsaid intermediate chamber and said return chamber, and a return passagecommunicating with said annular return chamber for leading saidlubricant fluid back to said lubrication system, an air inlet portcommunicating with said chamber on one side of said diaphragm, an airreceiver having sufcient air pressure therein to initially close saidair valve, a conduit connecting said air receiver with said inlet port,a solenoid valve normally closed when the power is on but open when thepower fails positioned in said conduit to allow the air pressure in saidair receiver to act when the solenoid is open, an orice means on saidair receiver to constrict the amount of pressure that can be deliveredthereto, and bleeder means in said air inlet port to coact with saidrestricting orice and said return means to allow the pressure in saidchamber to equalize to atmospheric pressure whereby the air valve willopen slowly and the lubricant fluid will be returned to the lubricationsystem to allow the shut down seal to close in accordance with thestopping time of said compressor.

WILLIAM H. CHURCH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,947,017 McHugh Feb. 13, 19342,236,274 Rice et al. i Mar. 25, 1941

